Prior art side dump railway cars typically utilize air cylinders positioned on one side of the car to lift that side causing the contents of the car to be dumped on the opposite side. Usually, two very large telescoping air cylinders are used on each side of the car for a total of four very expensive cylinders. Air cylinders are generally chosen to make use of the pressurized air supply present on trains. However, since air is compressible and quite springy the tilting action tends to be erratic and uncertain. The side dump car may stick in place momentarily until pressure builds and then move suddenly creating hazardous operation. In addition the size of the cylinders requires that they be carried quite low and outboard on the car making them highly susceptible to damage in the event of derailment. Furthermore, the large air cylinders must be custom built and are extremely expensive. A further disadvantage of air cylinders is encountered when the air continues to expand after the supply is shut off thus producing an additional and unwanted body movement. Greater tipping of the dump body shifts the center of gravity so as to relieve the pressure on the air cylinders. Consequently, the air may expand even more and tip the body even further. If this occurs near the over center point and the load is frozen or compacted or the door fails to open, it is possible to tip the car over. These problems are overcome by my invention as described hereinafter.